How to access cross object fields in lightning:datatable?

Hi,

I am sharing you the code for data table, it may give you a little help -

Component - 

<aura:component>
<!-- Imports -->
<aura:import library="lightningcomponentdemo:mockdataFaker" property="mockdataLibrary"/>

<!-- attributes -->
<aura:attribute name="data" type="Object"/>
<aura:attribute name="columns" type="List"/>

<!-- handlers-->
<aura:handler name="init" value="{! this }" action="{! c.init }"/>

<!-- the container element determine the height of the datatable -->
<div style="height: 300px">
<lightning:datatable
keyField="id"
data="{! v.data }"
columns="{! v.columns }"
hideCheckboxColumn="true"/>
</div>
</aura:component>

Controller - 

({
init: function (cmp, event, helper) {
cmp.set('v.columns', [
{label: 'Opportunity name', fieldName: 'opportunityName', type: 'text'},
{label: 'Account name', fieldName: 'accountName', type: 'text'},
{label: 'Close date', fieldName: 'closeDate', type: 'date'},
{label: 'Confidence', fieldName: 'confidence', type: 'percentage'},
{label: 'Amount', fieldName: 'amount', type: 'currency', typeAttributes: { currencyCode: 'EUR', maximumSignificantDigits: 5}},
{label: 'Contact Email', fieldName: 'contact', type: 'email'},
{label: 'Contact Phone', fieldName: 'phone', type: 'phone'},
{label: 'Website', fieldName: 'website', type: 'url', typeAttributes: { target: '_self'}},
{label: 'Address', fieldName: 'address', type: 'location'}
]);

var fetchData = {
opportunityName: "company.companyName",
accountName : "name.findName",
closeDate : "date.future",
amount : "finance.amount",
contact: "internet.email",
phone : "phone.phoneNumber",
website : "internet.url",
status : {type : "helpers.randomize", values : [ 'Pending', 'Approved', 'Complete', 'Closed' ] },
actionLabel : {type : "helpers.randomize", values : [ 'Approve', 'Complete', 'Close', 'Closed' ]},
confidenceDeltaIcon : {type : "helpers.randomize", values : [ 'utility:up', 'utility:down' ]}
};

helper.fetchData(cmp,fetchData, 10);
}
})

Helper - 

({
fetchData: function (cmp, fetchData, numberOfRecords) {
var dataPromise,
latitude,
longitude,
fakerLib = this.mockdataLibrary.getFakerLib();

fetchData.address = {type : function () {
return {
latitude : fakerLib.address.latitude(),
longitude : fakerLib.address.longitude()
}
}};

fetchData.confidence = { type : function () {
return fakerLib.random.number(100) + "%"
}};

dataPromise = this.mockdataLibrary.lightningMockDataFaker(fetchData,numberOfRecords);
dataPromise.then(function(results) {
cmp.set('v.data', results);
});
}
})

Hope this helps.